Sweep frequency vibrator
OwnerDennis E. Roesslerinventor
Life of this patent
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Abstract
A sweep frequency vibrator is set forth. It has an elongate cylindrical housing closed at the top and bottom ends. On the interior, there is a reactionary mass fixed to identical upper and lower piston ends. They are received in seal isolated chambers, one being formed in a moveable plug. The plug is moved to thereby vary the spacing of the chambers. As the frequency is changed, plug is moved to assure sufficient clearance from the excursion of the reactionary mass. Hydraulic oil under pressure is delivered to control valves, one for each piston end. The two control valves and piston ends have very short flow lines. Moreover the excursion permitted for the plug assures operation without bottoming out.
Claims17
A variable frequency seismic wave generator comprising:
- an elongate generally cylindrical housing having closed ends and a diameter enabling said housing to be positioned in a well borehole;
- a moveable reactionary mass within said housing, said reactionary mass supported by a pair of opposing piston ends;
- a first assembly defining a first fluid filled chamber configured to receive a first of said piston ends;
- and
- a second assembly defining a second fluid filled chamber configured to receive the second of said piston ends;
- and
- means for moving said first and second assemblies relative to one another to alter the relative volumes of said first and second chambers.
A method of creating a sweep frequency sonic wave, comprising the steps of:
- positioning a reactionary mass between a pair of piston ends located in fluid filled chambers spaced from said mass to enable said mass to vibrate as said piston ends move said mass;
- providing a cyclic flow of hydraulic fluid to act on said piston ends to initiate and sustain vibration of said reactionary mass;
- moving said chambers relative to one another to alter the vibration range of movement of said reactionary mass as a function of the desired vibration frequency;
- and
- monitoring the reactionary mass movement.
A method of forming a variable frequency vibration in a well borehole, comprising the steps of:
- positioning a housing in a well borehole wherein one end of said housing is closed by an end closure means and the remaining end of said housing is closed by a moveable plug;
- in said housing, positioning a reactionary mass having a pair of spaced piston ends to enable said mass and piston ends to move as a unit;
- positioning upper and lower fluid flow control valves adjacent to said piston ends;
- providing high pressure fluid flow through said control valves to said piston ends to alternately move said reactionary mass and said piston ends subject to said high pressure fluid flow;
- controlling the control valves to alter the position of said moveable plug in said housing to vary the direction of movement of said reactionary mass and said piston ends, and thereby to vary the frequency and amplitude of vibration from said reactionary mass.
Dependencies are inferred from the claim text.